The differential scatter-air ratio and differential backscatter factor method combined with the density scaling theorem.
The differential scatter-air ratio and differential backscatter factor method combined with the density scaling theorem.
复制标题
微分散射空气比和微分后向散射因子方法与密度缩放定理相结合。
DOI：
10.1118/1.595576
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发表时间：
1984
期刊：
影响因子：
3.8
通讯作者：
T. Ishito
中科院分区：
文献类型：
--
作者：
A. Iwasaki;T. Ishito
使用奥康纳密度缩放定理，推导出两个基本方程来表达均质和异质体模中的散射剂量计算：(i) 用于计算前向散射的微分散射-空气比，以及 (ii) 用于计算后向散射的微分后向散射因子。在两个方程的推导中，沿散射元件和计算点之间的线的相对电子密度已被平均以考虑散射衰减。每个方程表示在计算点每单位初级剂量、每单位相对电子密度、每单位体积在散射元件处的前向或反向散射量。均质体模和异质体模中的初级剂量计算均使用简单的指数衰减定律进行。除了存在电子不平衡的界面或附近区域以及场边界周围区域外，使用主要和散射剂量计算程序在均质软组织模型以及异质软木和铝模型中使用 Co-60 伽马射线进行的实验获得了令人满意的剂量计算。
Using the O'Connor density scaling theorem, two basic equations have been derived to express scatter dose calculations in both homogeneous and heterogeneous phantoms: (i) the differential scatter-air ratio for calculating the frontscatter, and (ii) the differential backscatter factor for calculating the backscatter. In the derivation of both equations the relative electron density along the line between the scattering element and the calculation point has been averaged to account for scatter attenuation. Each equation expresses the amount of front or backscatter at the point of calculation per unit primary dose, per unit relative electron density, per unit volume at the scattering element. Primary dose calculations in both a homogeneous and a heterogeneous phantom have been carried out using a simple exponential attenuation law. Except in the area of or near interfaces and the area around field borders where there is electron disequilibrium, satisfactory dose calculations have been obtained using the primary and scatter dose calculation procedure for experiments done with Co-60 gamma rays in homogeneous soft tissue phantoms and in heterogeneous cork and aluminum phantoms.